Research that went into developing the highly specialized technology for space travel has resulted in many unexpected practical applications back on earth. Out of the engineering that produced rocket motors, liquid propellants (推进剂), space suits, and other necessities of space flight came by-products that no one had anticipated. Equipment and procedures designed for astronauts and space flights have been successfully adapted for use in medicine, industry, and the home. These valuable products of space research, called spin-offs, have improved the quality of life on earth in many ways.Some of the best-known examples of spin-offs from space research are found in hospitals and doctors' offices. One such example is the sight switch, which was originally developed to allow astronauts to control their spacecraft without ______ their hands. The sight46. The word "such" (Para. 2) refers to _______.A. highly specialized technology for space travelB. research in hospitalsC. spin-offs from space researchD. research in doctors' offices

我们来一步一步分析这道题目。

题目要求我们判断第二段中单词 “such” 指代的是什么。

首先，我们来看原文第二段的内容（根据你提供的内容）：

> Some of the best-known examples of spin-offs from space research are found in hospitals and doctors' offices. One such example is the sight switch, which was originally developed to allow astronauts to control their spacecraft without ____ their hands.

我们先理解这段话的意思：

• “Some of the best-known examples of spin-offs from space research are found in hospitals and doctors' offices.”
  意思是：“航天研究的一些最著名的衍生产品（即‘spin-offs’）可以在医院和医生的办公室中找到。”

• 接着说：“One such example is the sight switch...”
  意思是：“一个这样的例子就是‘sight switch’（视线开关）……”

现在我们重点分析 “such” 这个词。

“such” 是一个指示代词，意思是“这样的”，它必须指代前文提到的某个同类事物。在这里，“one such example” 中的 “such” 指的是前一句中提到的“examples of spin-offs from space research”。

换句话说：

• 前一句说：航天研究的衍生产品（spin-offs）的一些著名例子出现在医院和医生办公室。
• 然后说：其中一个这样的例子是视线开关。

所以，“such” 指的就是“来自航天研究的衍生产品（spin-offs）的例子”。

因此，“such” 指代的是“spin-offs from space research”。

我们再来看选项：

A. highly specialized technology for space travel
→ 这是第一段提到的内容，但不是“such”前面直接提到的“examples”，范围太大，不准确。

B. research in hospitals
→ 文中没有说医院的研究，而是说航天技术被用在医院，错误。

C. spin-offs from space research
→ 正确！这正是前一句的主语，也是“such”所指代的内容。

D. research in doctors' offices
→ 同样，文中没有提到医生办公室的研究，而是说这些衍生产品出现在那里，错误。

正确答案是：C. spin-offs from space research

解题过程总结：

1. 找到“such”所在的句子：“One such example is the sight switch...”
2. 分析前一句：“Some of the best-known examples of spin-offs from space research are found in hospitals and doctors' offices.”
3. 明确“such”指代前文提到的“examples”，而这些例子是“spin-offs from space research”的例子。
4. 因此，“such”指的就是“来自航天研究的衍生产品”。
5. 对比选项，C 项完全匹配。

答案：\boxed{C}